In countries throughout the world, a postal customer may obtain postage from the postal authority in several ways, including the purchase of stamps and the use of a postage meter. The customer has at least two security concerns no matter what method is used to obtain postage from the postal authority. First, the customer is concerned that only his authorized agents purchase postage from the postal authority. Second, the customer is concerned with limiting usage of the purchased postage to authorized persons. This is a particular concern in an office environment where there are a large number of personnel.
When stamps are involved, their purchase may be controlled through various accounting techniques, and their use is generally limited by physically controlling the stamps themselves. For example, the stamps are kept in a locked location, such as a drawer, and only authorized personnel have access to the stamps. Such physical controls may also be used for limiting access to postage machines. Due to the size of postage machines, however, such physical control mechanisms may be of great inconvenience.
Typically, a postage meter is left out in an open area where there is little access control to the physical area itself. Thus, limiting the operation of the machine must be accomplished in a manner in which it is not necessary to limit access to the area containing the machine. In some postage machines, limiting operation to authorized personnel has been accomplished through use of physical means, most typically a key without which the machine will not operate. Physical controls similar to those used for stamps are then used to limit access to the key to authorized personnel.
With electronic postage meters, it may be possible to limit operation of the machine to authorized personnel through the use of a Personal Identification Number (PIN), in addition to physical controls, or in combination therewith. Furthermore, some electronic postage meters are capable of purchasing postage remotely, obviating the necessity of physically taking the postage meter to the postal authority for the addition of postage, and a PIN may be used to limit those persons who are authorized to purchase additional postage. When a PIN is involved, however, there is a risk that some unauthorized person may obtain knowledge of the PIN, for example, by observing the entry of the PIN by an authorized person. When the PIN becomes compromised, or knowledge of it is no longer limited to authorized personnel, the PIN ceases to be an effective means of limiting the operation of the postage meter to authorized personnel.
When a PIN has been compromised, or is suspected of having been compromised, the PIN must be changed in order to once again become an effective means of limiting the operation of the postage meter to authorized personnel. Changing a PIN, however, is not a trivial matter. Generally, the supplier of the postage meter must be consulted, which at a minimum, increases the amount of time the compromised PIN is no longer an effective control means.